* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  ul {
    list-style-type: none;
  }
  
  #app {
    font-family: "Microsoft YaHei", Arial, sans-serif;
  }
  
  .container {
    max-width: 400px;
    margin: 40px auto;
    padding: 20px;
    border: 1px solid #ccc;
    border-radius: 10px;
  }
  
  .container h1 {
    text-align: center;
    font-size: 24px;
    margin-bottom: 20px;
  }
  
  .container .add-todo {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
  }
  
  .container .add-todo input {
    flex: 1;
    margin-right: 10px;
    padding: 5px;
    border: 1px solid #ccc;
    border-radius: 5px;}
   
    .container .add-todo input:focus {
      outline: none;
      border-color: #007bff;
    }
  
  .container .add-todo input::placeholder {
      color: #ccc;
    }
  
  .container .add-todo button {
    box-sizing: content-box;
    padding: 5px 10px;
    background-color: #007bff;
    color: #fff;
    border: none;
    border-radius: 5px;
    cursor: pointer;
  }
  
  .container .filter {
    margin-bottom: 10px;
  }
  
  .container .filter button {
    padding: 5px 10px;
    background-color: #007bff;
    color: #fff;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    margin-right: 10px;
  
  }
  
  .container .search {
    margin-bottom: 10px;
  }
  
  .container .search input {
    width: 100%;
    padding: 5px;
    border: 1px solid #ccc;
    border-radius: 5px;
    line-height: 30px;
    height: 30px;
    vertical-align: middle;
  
    &::placeholder {
      color: #ccc;
    }
  
    &:focus {
      outline: none;
      border-color: #007bff;
    }
  }
  
  .container ul {
    margin-bottom: 10px;
  }
  .container ul li {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 5px;
    background-color: #f8f8f8;
    transition: all 0.3s ease;
    &:hover {
      transform: translateY(-5px);
    }
  }
  .container ul li .checkbox-group {
    display: flex;
    align-items: center;
    margin-right: 10px;
    & input {
      margin-right: 5px;
      vertical-align: middle;
      cursor: pointer;
      margin-top: 2px;
    }
    & span {
      flex: 1;
      vertical-align: middle;
    }
  }
  
  .container ul li .btn-group button {
    margin-left: 10px;
    padding: 5px 10px;
    background-color: #007bff;
    color: #fff;
    border: none;
    border-radius: 5px;
    cursor: pointer;
  }
  
  
  .completed {
    text-decoration: line-through;
    color: gray;
  }